Refrigerant composition comprising difluoromethane, 1,1,1-trifluoroethane and 1,1,1,2-tetrafluoroethane

ABSTRACT

A refrigerant composition that can be a substitute for chlorodifluoromethane (HCFC-22) comprises: (a) a first constituent of difluoromethane, (b) a second constituent of 1,1,1-trifluoroethane, (c) a third constituent of 1,1,1,2-tetrafluoroethane, and (d) a fourth constituent selected from the group consisting of 1,1-difluoroethane, 1,1,1,2,3,3,3-heptafluoropropane, 1,1,1,2,3,3-hexafluropropane and butane.

BACKGROUND OF THE INVENTION

1. Field of the Invention

The present invention relates to a refrigerant composition that canreplace chlorodifluoromethane (referred to as ‘HCFC-22’, hereinafter)which has been known to destroy the ozone layer of the Earth.

2. Description of the Background Art

Since chlorofluorocarbon (referred to as ‘CFC’, hereinafter) compoundswere revealed as substances destroying the ozone layer of the Earth,they have been restricted in production and use according to theMontreal Protocol. In developed countries, the use of CFC compounds hasalready been banned since 1996. Not so much serious as CFC compounds,but HCFC compounds such as HCFC-22 have also known to have considerableeffects in causing damages to the ozone layer. For this reason, arestriction has been made to gradually reduce the use of HCFC compounds,and a plan has also been made to ban its use around 2030.

Many researches are being conducted to develop-a substitute material forHCFC-22. Representative substitute materials for HCFC-22 are HFC-407Cand HFC-410A proposed by the American Society of Heating, Refrigeratingand Air-conditioning Engineers (ASHRAE). HFC-407C is a refrigerantcomposition of HFC-32/125/134a in a ratio of 23/25/52 based on weightpercent. Meanwhile, HFC-410A is a refrigerant composition of HFC-32/125in a ratio of 50/50 based on weight percent.

In addition, U.S. Pat. No. 5,080,823 discloses a refrigerant compositionof HFC-143a/propane, U.S. Pat. No. 5,211,867: HFC-125/143a, U.S. Pat.No. 5,234,613: HFC-32/propane, U.S. Pat. No. 5,236,611 ofPFC-218/HFC-143a, U.S. Pat. No. 5,290,466: HFC-32/134a/134, U.S. Pat.No. 5,340,490: HFC-23/CO₂ and HFC-23/116/CO₂, U.S. Pat. No. 5,403,504:HFC-125/32, U.S. Pat. No. 5,429,740: HFC-23/134a U.S. Pat. No.5,538,660: HFC-32/HFC-134a/FC-41 and HFC-32/HFC-134a/PFC-218, and U.S.Pat. No. 5,643,492: HFC-32/125/134a.

Also, Japanese Patent Laid-open Publication No. 172386/1991 discloses arefrigerant composition of HFC-32/125/143a, Japanese Patent Laid-openPublication No. 170594/1991: HFC-23/125/134a, Japanese Patent Laid-openPublication No. 170593/1991: HFC-23/143a/134a, Japanese Patent Laid-openPublication No. 170591/1991: HFC-23/143a/134a, Japanese Patent Laid-openPublication No. 170590/1991: HFC-125/134a/32, Japanese Patent Laid-openPublication No. 170589/1991: HFC-23/143a/152a, Japanese Patent Laid-openPublication No. 170588/1991: HFC-125/143a/134a, Japanese PatentLaid-open Publication No. 170585/1991: HFC-32!125/134a, Japanese PatentLaid-open Publication No. 170584/1991: HFC-23/134a/152a, Japanese PatentLaid-open Publication No. 170583/1991: HFC-125/143a/32, Japanese PatentLaid-open Publication No. 222893/1992: HFC-32/125, Japanese PatentLaid-open Publication No. 154887/1992: HFC-134/152a, Japanese PatentLaid-open Publication No. 117645/1993: HFC-23/134a/propane, JapanesePatent Laid-open Publication No. 117643/1993: HFC-125/134a/propane,Japanese Patent Laid-open Publication No. 65561/1994:HFC-23/152a/PFC-218, Japanese Patent Laid-open Publication No.128872/1994: HFC-32/PFC-218, Japanese Patent Laid-open Publication No.173462/1995: HFC-32/125-RC-318, Japanese Patent Laid-open PublicationNo. 173462/1995: HFC-143a/125/134a/heptane, Japanese Patent Laid-openPublication No. 176537/1996: PFC-218/RC-270/HFC-152a, Japanese PatentLaid-open Publication No. 151569/1996: propane/RC-270/HFC-134a, JapanesePatent Laid-open Publication No. 127767/1996: HFC-32/134a/RC-318,Japanese Patent Laid-open Publication No. 25480/1997:HFC-32/134a/125/isobutane, Japanese Patent Laid-open Publication No.208941/1997: HFC-32/152a/125/RC-270, and Japanese Patent Laid-openPublication No. 221664/1997: HFC-125/143a/134a/RC-270.

Also, Korean Patent Laid-open Publication No. 91-9902 discloses arefrigerant composition of HFC-23/32/152a, HFC-23/125/152a,HFC-32/143a/152a, HFC-32/125/125a, HFC-23/143a/152a, Korean PatentLaid-open Publication No. 91-9903: HFC-23/32/134, HFC-23/32/134a,HFC-23/125/134, HFC-32/125/134, HFC-23/143a/134a, HFC-125/143a/134a,HFC-125/143a/134, Korean Patent Laid-open Publication No. 96-4485:HFC-32/23/134a, Korean Patent Laid-open Publication No. 96-701168:HFC-227ea/HFC-152a, Korean Patent Laid-open Publication No. 97-704853:HFC-134a/HCFC-124/butane.

SUMMARY OF THE INVENTION

Therefore, an object of the present invention is to provide a novelrefrigerant composition that can be used as a substitute for HCFC-22,without containing a substance that destroys the ozone layer of theEarth.

DETAILED DESCRIPTION OF THE INVENTION

The above and other objects of the present invention, as embodied andbroadly described herein, are achieved by providing a refrigerantcomposition, comprising (a) a first constituent of difluoromethane(hereinafter referred to as ‘HFC-32’), (b) a second constituent of1,1,1-trifluoroethane (hereinafter referred to as ‘HFC-143a’), (c) athird constituent of 1,1,1,2-tetrafluoroethane (hereinafter referred toas ‘HFC-134a’) and (d) a fourth constituent selected from the groupconsisting of 1,1-difluoroethane (hereinafter referred to as‘HFC-152a’), 1,1,1,2,3,3,3-heptafluoropropane (hereinafter referred toas ‘HFC-227ea’), 1,1,1,2,3,3-hexafluropropane (hereinafter referred toas ‘HFC-236ea’) and butane (hereinafter referred to as ‘R-600’).

Advantageously, the refrigerant composition of the present inventiondoes not have any risk to damage the ozone layer, and therefore, thereis no concern to be restricted in its use in the future. The abovecompounds that can be a constituent of the refrigerant composition ofthe present invention have already been produced, or research isactively conducted to produce them for later use. Their use is newlyadded through the present invention, and therefore they can be used moreeffectively.

The refrigerant composition of the present invention has been appliedfor a refrigeration system having a compressor, a condenser, anexpansion valve and an evaporator to evaluate a coefficient ofperformance (COP), a volumetric capacity (VC) of the refrigerant andpressures in the compressor and evaporator. The novel refrigerantcomposition proposed by the present invention has been evaluated to havealmost the same level in performance compared with that of HFC-407C orHFC-410 that has been proposed as a substitute refrigerant for HFC-22,so that it can be used as a substitute for HFC-22.

It is preferred that the refrigerant composition of the presentinvention comprises the first constituent in the range of 20-70 wt. %,the second and third constituents in the ranges of 10-50 wt. %,respectively, and the fourth constituent in the range of 5-40 wt. %.Preferred embodiments of the refrigerant composition of the presentinvention comprising specific compounds will now be described.

Where the refrigerant composition comprising HFC-32, HFC-143a, HFC-134aand HFC-152a, the contents of constituents are in the ranges of 20-70wt. %, 10-50 wt. %, 10-50 wt. % and 10-40 wt. %, respectively, andpreferably, in the ranges of 30-60 wt. %, 20-40 wt. %, 20-40 wt. % and20-30 wt. %, respectively.

Where the refrigerant composition comprising HFC-32, HFC-143a, HFC-134aand HFC-227ea, the contents of constituents are in the ranges of of30-70 wt. %, 10-50-wt. % 10-50 wt. % and 10-30 wt. %, respectively, andpreferably, in the ranges of 20-60 wt. %, 20-40 wt. %, 20-40 wt. % and15-25 wt. %, respectively.

Where the refrigerant composition comprising HFC-32, HFC-143a, HFC-134aand HFC-236ea, the contents of constituents are in the ranges of 40-70wt. %, 10-40 wt. %, 10-40 wt. % and 5-15 wt. %, respectively, andpreferably, in the ranges of 50-60 wt. %, 20-30 wt. %, 20-30 wt. % and8-12 wt. %, respectively.

Where the refrigerant composition comprising HFC-32, HFC-143a, HFC-134aand R-600, the contents of constituents are in the ranges of 40-70 wt.%, 10-40 wt. %, 10-40 wt. % and 5-13 wt. %, respectively, andpreferably, in the ranges of 50-60 wt. %, 20-30 wt. %, 20-30 wt. % and7-10 wt. %, respectively.

EXAMPLES

The present invention will now be explained in more detail with thecomparative examples and examples evaluating the performance of therefrigerant compositions. It is to be understood that these examples aremerely illustrative and not intended to limit the scope of the presentinvention thereto.

By using a refrigeration system having a compressor, a condenser, anexpansion valve and an evaporator, main factors for evaluatingrefrigerant performance including a coefficient of performance (COP), avolumetric capacity (VC) of the refrigerant, pressure in the evaporator(P_(L)) and pressure in the condenser (P_(H)) were measured for HCFC-22,HFC-407C and HFC-410A (Comparative Examples 1 to 3), and the refrigerantcompositions of the present invention (Examples 1 to 4 under thefollowing conditions:

-   Refrigeration capacity: 2 kW-   Overall Heat Transfer Coefficient in Evaporator (UA): 0.20 kW/K-   Overall Heat Transfer Coefficient in Condenser (UA): 0.24 kW/K-   Degree of Subcooling in Condenser: 5° C.-   Degree of Superheating in Evaporator: 5° C.-   Efficiency of Compressor: 0.8-   Temperature of Secondary Fluid at Inlet of Condenser: 25° C.-   Temperature of Secondary Fluid at Outlet of Condenser: 35° C.-   Temperature of Secondary Fluid at Inlet of Evaporator: 15° C.-   Temperature of Secondary Fluid at Outlet of Evaporator: 5° C.

Comparative Examples 1-3

Performance was evaluated for HCFC-22, HFC-407C and HFC-410A under theabove-described conditions, of which results are as shown in Table 1.

TABLE 1 HFC- HFC- HFC- HFC- Comparative 22 32 125 134a VC P_(L) P_(H)Example No. Refrigerant (wt. %) (wt. %) (wt. %) (wt. %) COP (kJ/m³)(kPa) (kPa) 1 HCFC-22 100 — — — 5.45 3338 455 1254 2 HFC-407C — 23 25 524.98 3412 460 1445 3 HFC-410A — 50 50 — 5.31 5117 730 1993

It is noted in Table 1 that HFC-407C has a lower COP compared withHCFC-22 while having almost the same VC and pressures. Compared withHCFC-22, HFC-410A has a similar COP and a higher VC, while having alittle higher pressures. As far as the performance of a refrigerantcomes within the ranges as described above, the refrigerant has beenevaluated to be used as a substitute refrigerant for HCFC-22.Accordingly, in the following examples, performance of the refrigerantcompositions according to the present invention was evaluated andcompared with those of the refrigerant compositions of comparativeexamples.

Example 1

Performances of the refrigerant compositions comprisingHFC-32/HFC-143a/HFC-134a/HFC-152a having various mixed ratios wereevaluated, and the results are as shown in Table 2.

TABLE 2 Compo- HFC-32 HFC-143a HFC-134a HFC-152a VC P_(L) P_(H) sition(wt. %) (wt. %) (wt. %) (wt. %) COP (kJ/m³) (kPa) (kPa) 1 30 40 20 205.05 3375.8 462.1 1398.7 2 30 20 20 30 5.13 3365.6 443.9 1359.0 3 30 1050 10 5.14 3387.1 444.5 1373.1 4 30 20 40 10 5.12 3534.4 472.8 1436.7 530 40 20 10 5.10 3834.3 532.8 1563.2 6 60 10 10 20 5.23 4206.8 561.31631.8 7 60 20 10 10 5.29 4518.6 617.3 1739.2 8 40 30 10 20 5.15 3904531.3 1561.5 9 40 10 10 40 5.14 3430.7 445.8 1369.8 10 40 10 30 20 5.183637.0 477.8 1445.7 11 50 10 30 10 5.22 4046.9 539.2 1586.1 12 50 10 1030 5.17 3804.5 500.9 1501.3 13 30 50 10 10 5.10 3986.8 564.6 1626.7 1440 40 10 10 5.17 4191.3 585.8 1672.5 15 70 10 10 10 5.33 4644.1 628.01761.6

As noted in Table 2, performances by each item of the refrigerantcompositions having the above-described ratios are in the range betweenHFC-407C and HFC-410A, so that they can be used as a substituterefrigerant for HCFC-22.

Example 2

Performances of the refrigerant compositions comprisingHFC-32/HFC-143a/HFC-134a/HFC-227ea having various mixed ratios wereevaluated, and the results are as shown in Table 3.

TABLE 3 Compo- HFC-32 HFC-143a HFC-134a HFC-227ea VC P_(L) P_(H) sition(wt. %) (wt. %) (wt. %) (wt. %) COP (kJ/m³) (kPa) (kPa) 1 30 10 40 205.00 3520.8 476.5 1487.5 2 30 20 30 20 5.00 3706.0 511.4 1560.7 3 30 3040 10 5.05 3828.3 533.1 15886 4 30 10 50 10 5.05 3484.1 465.2 1445.9 530 50 10 10 5.06 4191.2 609.2 1734.0 6 30 40 20 10 5.05 4007.5 570.01660.3 7 40 10 20 30 5.04 4039.3 558.2 1677.9 8 40 10 40 10 5.13 3883.4523.0 1573.0 9 40 30 10 20 5.13 4350.4 619.1 1769.6 10 40 40 10 10 5.174444.6 636.6 1785.4 11 50 10 30 10 5.21 4269.7 580.0 1686.9 12 50 10 1030 5.18 4513.8 630.7 1809.5 13 60 20 10 10 5.35 4855.6 677.8 1858.4 1470 10 10 10 5.41 5014.0 691.9 1882.3

As noted in Table 3, performances by each item of the refrigerantcompositions having the above-described ratios are in the range betweenHFC-407C and HFC-410A, so that they can be used as a substituterefrigerant for HCFC-22.

Example 3

Performances of the refrigerant compositions comprisingHFC-32/HFC-143a/HFC-134a/HFC-236ea having various mixed ratios wereevaluated, and the results are as shown in Table 4.

TABLE 4 Compo- HFC-32 HFC-143a HFC-134a HFC-236ea VC P_(L) P_(H) sition(wt. %) (wt. %) (wt. %) (wt. %) COP (kJ/m³) (kPa) (kPa) 1 40 10 40 105.01 3720.1 496.9 1542.1 2 40 20 30 10 5.02 3897.1 531.3 1610.7 3 40 3020 10 5.04 4081.7 567.9 1679 4 40 40 10 10 5.07 4272.9 606.8 1748.1 5 5010 30 10 5.10 4109.4 554.5 1657.2 6 50 20 20 10 5.14 4303.2 592.1 1724.87 50 30 10 10 5.17 4504.0 632.1 1792.9 8 60 10 20 10 5.22 4498.2 612.61761.0 9 60 20 10 10 5.27 4709.9 653.6 1828.3 10 70 10 10 10 5.35 4888.6671.2 1855.4 11 50 10 35 5 5.16 4136.7 556.9 1647.6 12 55 20 17 8 5.214513.4 623.1 1774.4 13 60 10 15 15 5.13 4453.0 609.0 1776.5 14 45 33 1012 5.08 4326.4 609.0 1761.7

As noted in Table 4, performances by each item of the refrigerantcompositions having the above-described ratios are in the range betweenHFC-407C and HFC-410A, so that they can be used as a substituterefrigerant for HCFC-22.

Example 4

Performances of the refrigerant compositions comprisingHFC-32/HFC-143a/HFC-134a/R-600 having various mixed ratios wereevaluated, and the results are as shown in Table 5.

TABLE 5 Compo- HFC-32 HFC-143a HFC-134a R-600 VC P_(L) P_(H) sition (wt.%) (wt. %) (wt. %) (wt. %) COP (kJ/m³) (kPa) (kPa) 1 40 10 40 10 5.003836.4 532.3 1599 2 40 20 30 10 5.01 3995.1 565.1 1663 3 40 30 20 105.02 4154.9 599.2 1726.9 4 40 40 10 10 5.03 4316.3 634.9 1791.2 5 50 1030 10 5.09 4220.6 592.5 1719.6 6 50 20 20 10 5.11 4398.4 627.9 1782.6 750 30 10 10 5.13 4569.7 664.8 1846 8 60 10 20 10 5.20 4624.2 653.71829.7 9 60 20 10 10 5.23 4807.8 692.2 1892.7 10 70 10 10 10 5.33 5028.1716.6 1931.7 11 55 20 20 5 5.25 4613.5 648.7 1806.5 12 70 10 7 13 5.094813.4 694.8 1937.3 13 60 20 13 7 5.30 4828.8 687.0 1872.7

As noted in Table 5, performances by each item of the refrigerantcompositions having the above-described ratios are in the range betweenHFC-407C and HFC-410A, so that they can be used as a substituterefrigerant for HCFC-22.

1. A refrigerant composition comprising: (a) a first constituent ofdifluoromethane, (b) a second constituent of 1,1,1-trifluoroethane, (c)a third constituent of 1,1,1,2-tetrafluoroethane, and (d) a fourthconstituent butane, wherein the contents of the first, second, third andfourth constituents are in the ranges of 20-70 wt. %, 10-50 wt. %, 10-50wt. % and 5-40 wt. %, respectively.
 2. The refrigerant compositionaccording to claim 1, wherein the content of the fourth constituent isin the range of 10-40 wt. %.
 3. The refrigerant composition according toclaim 1, wherein the content of the first constituent is in the range of30-70 wt. % and the content of the fourth constituent is in the range of10-30 wt. %.
 4. The refrigerant composition according to claim 1,wherein the contents of the first, second, third and fourth constituentsare in the ranges of 40-70 wt. %, 10-40 wt. %, 10-40 wt. % and 5-15 wt.%, respectively.
 5. The refrigerant composition according to claim 1,wherein the content of the fourth constituent is in the range of 5-13wt. %.